Project Summary This proposal is for the University of Houston College of Optometry (UHCO) to serve as one of two clinical centers for the Bifocal Lenses in Nearsighted Kids 2 (BLINK2) Study, which will continue to follow children enrolled in the original BLINK Study randomized clinical trial. The primary goal of BLINK2 is to determine correlates of myopia progression using non-invasive measurements of biomarkers (choroidal thickness and intrinsically photosensitive retinal ganglion cell (ipRGC)-mediated pupil function) and outdoor light exposure in children. If multifocal contact lenses slow the progression of myopia by 30% or more compared to single vision contact lenses during the BLINK Study, BLINK2 will also answer important questions about the consequences and mechanism of the treatment effect, such as whether multifocal contact lens wear alters accommodative function and whether or not the treatment benefit is transient. Specifically, BLINK2 will investigate whether myopia progression is slowed or simply delayed by multifocal contact lens wear and whether a ?rebound? in myopia progression occurs, an increase in progression rate, after discontinuation of multifocal contact lenses. BLINK2 will identify the myopic children who will most benefit from myopia control by determining those who are most likely to progress, thereby maximizing the potential for benefit and minimizing risk. BLINK2 will accomplish this goal by investigating the effect on progression of the most important ocular and environmental risk factors recently hypothesized to control the growth of the eye. The project will collect the most extensive longitudinal dataset ever on choroidal thickness in childhood myopia. BLINK2 will test the important question of whether time outdoors and light exposure influence myopia progression after onset and whether these effects are mediated by ipRGCs. If soft multifocal contact lenses show a clinically meaningful slowing of myopia progression during the BLINK Study, BLINK2 will also answer many important questions asked routinely by clinicians: whether accommodation is affected by multiple years of multifocal contact lens wear in children; whether multifocal contact lenses slow or simply delay myopia progression; and whether myopia progression increases following discontinuation of soft multifocal contact lens wear. BLINK2 seeks to maximize the benefit while lowering the risk of multifocal contact lens wear for myopia control while answering important scientific and clinical questions about the consequences and mechanism of myopia progression. This application details the UHCO Clinical Center's ability to enroll children from the BLINK Study to continue following them for an additional three years. The application also documents that UHCO has the personnel, experience, equipment, and facilities needed to successfully conduct this study in accordance with the study Manual of Procedures (MOP). Complete details regarding the study rationale, design, and methods are contained in the MOP, which is submitted with the Study Chair application.